Luo Fei, Deng Xiong, Liu Yue, Yan Yueming
College of Life Science, Capital Normal University, Beijing, 100048, China.
Hubei Collaborative Innovation Center for Grain Industry (HCICGI), Yangtze University, Jingzhou, 434025, China.
Bot Stud. 2018 Dec 8;59(1):28. doi: 10.1186/s40529-018-0245-7.
Wheat (Triticum aestivum L.) serves as important grain crop widely cultivated in the world, which is often suffered by drought stress in natural conditions. As one of the most important post translation modifications, protein phosphorylation widely participates in plant abiotic stress regulation. In this study, we performed the first comparative analysis of phosphorylated protein characterization in flag leaves and developing grains of elite Chinese bread wheat cultivar Zhongmai 175 under water deficit by combining with proteomic approach and Pro-Q Diamond gel staining.
Field experiment showed that water deficit caused significant reduction of plant height, tiller number, ear length and grain yield. 2-DE and Pro-Q Diamond gel staining analysis showed that 58 proteins were phosphorylated among 112 differentially accumulated proteins in response to water deficit, including 20 in the flag leaves and 38 in the developing grains. The phosphorylated proteins from flag leaves mainly involved in photosynthesis, carbohydrate and energy metabolism, while those from developing grains were closely related with detoxification and defense, protein, carbohydrate and energy metabolism. Particularly, water deficit resulted in significant downregulation of phosphorylated modification level in the flag leaves, which could affect photosynthesis and grain yield. However, some important phosphorylated proteins involved in stress defense, energy metabolism and starch biosynthesis were upregulated under water deficit, which could benefit drought tolerance, accelerate grain filling and shorten grain developing time.
The modification level of those identified proteins from flag leaves and grains had great changes when wheat was suffered from water deficit, indicating that phosphoproteins played a key role in response to drought stress. Our results provide new insights into the molecular mechanisms how phosphoproteins respond to drought stress and thus reduce production.
小麦（Triticum aestivum L.）是世界上广泛种植的重要粮食作物，在自然条件下常遭受干旱胁迫。蛋白质磷酸化作为最重要的翻译后修饰之一，广泛参与植物非生物胁迫调控。在本研究中，我们结合蛋白质组学方法和Pro-Q Diamond凝胶染色，首次对中国优质面包小麦品种中麦175在水分亏缺条件下旗叶和发育籽粒中磷酸化蛋白质的特征进行了比较分析。
田间试验表明，水分亏缺导致株高、分蘖数、穗长和籽粒产量显著降低。二维电泳和Pro-Q Diamond凝胶染色分析表明，在112个响应水分亏缺差异积累的蛋白质中，有58个蛋白质发生了磷酸化，其中旗叶中有20个，发育籽粒中有38个。旗叶中的磷酸化蛋白质主要参与光合作用、碳水化合物和能量代谢，而发育籽粒中的磷酸化蛋白质与解毒和防御、蛋白质、碳水化合物和能量代谢密切相关。特别是，水分亏缺导致旗叶中磷酸化修饰水平显著下调，这可能影响光合作用和籽粒产量。然而，一些参与胁迫防御、能量代谢和淀粉生物合成的重要磷酸化蛋白质在水分亏缺条件下上调，这可能有利于耐旱性，加速籽粒灌浆并缩短籽粒发育时间。
当小麦遭受水分亏缺时，从旗叶和籽粒中鉴定出的那些蛋白质的修饰水平发生了很大变化，表明磷酸化蛋白质在响应干旱胁迫中起关键作用。我们的结果为磷酸化蛋白质如何响应干旱胁迫从而降低产量的分子机制提供了新的见解。
